First Look At Yahoo! CEO Marissa Mayer's Baby Boy

The new mom tweeted a photo of her beautiful baby boy, Macallister, as they attended YaBoo—the company's kiddy Halloween party.

marissamayer @marissamayer

One month old - Macallister and me heading to YaBoo, the children's Halloween party at @Yahoo! http://t.co/TNxVnV2K

Tue, 30 Oct 2012 19:44:10 +0000

One month old - Macallister and me heading to YaBoo, the children's Halloween party at @Yahoo! http://t.co/TNxVnV2K-- marissamayer